Stator winding pattern for hairpin drive motor

ABSTRACT

A stator winding pattern of a hairpin drive motor includes a stator with 8 poles and 48 slots of a distribution winding where a hairpintype of flat coil is inserted into a slot of a stator core and configured by a full pitch winding implementing 6 pitches of 3 phases and 2 in parallel, the pitch being a distance between adjacent slots, characterized in that: first to fourth layers are formed in the slot of the stator core in a radial direction of the stator core; and when a first layer or a fourth layer is set as a draw out part of one phase in an optional reference slot, a first draw out part of a different phase is formed in a draw out slot having 28 pitches in a slot forward direction in a same layer based on the reference slot, and a second draw out part of the different phase is formed in a draw out slot having 20 pitches in a slot reverse direction in the same layer based on the reference slot.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2014-0172124 filed in the Korean IntellectualProperty Office on Dec. 3, 2014, the entire contents of which areincorporated herein by reference.

BACKGROUND OF THE DISCLOSURE

(a) Technical Field

Embodiments of the present disclosure relate generally to a drive motorfor an environmentally friendly vehicle, and more particularly, to astator winding pattern of a hairpin drive motor capable of minimizing amaximum potential difference at an adjacent section between phases in ahairpin drive motor.

(b) Description of the Related Art

In general, environmentally friendly vehicles, such as a hybrid vehicleor an electric vehicle, may generate a driving torque by an electricmotor (hereinafter referred to as “drive motor”) for obtaining arotating force based on electrical energy. A hybrid vehicle can run inan electric vehicle (EV) mode (i.e., a pure electric mode) using onlypower of a drive motor or a hybrid electric vehicle (HEV) mode usingdriving torques of both an engine and a drive motor for power.Meanwhile, an electric vehicle runs using solely the torque of the drivemotor as power.

For example, a drive motor used as a power source for an environmentallyfriendly vehicle is generally a permanent magnet synchronous motor(PMSM). The drive motor as a PMSM typically includes a stator togenerate a magnetic flux, a rotor spaced apart from the stator by apredetermined gap, and a permanent magnet installed at the rotor. Thestator includes a plurality of slots which are formed at an innerperipheral portion of a stator core, and a stator coil is wound in theslots. Accordingly, if an AC current is applied to a stator coil, thestator generates a rotation magnetic field so that a rotation torque maybe generated in the stator due to the rotation magnetic field.

Meanwhile, the drive motor is classified into a distribution windingdrive motor and a concentrated winding drive motor depending on awinding scheme of the stator coil. A stator of the distribution windingdrive motor is divided into a segment coil stator and a distributionwinding coil stator according to a winding scheme of the coil. Thesegment coil stator is a stator for inserting a coil in a slot of astator core after primarily molding the coil to have a predeterminedshape in advance. The distribution winding coil stator inserts a coilassembly in a slot of the stator core.

Output of the drive motor is proportional to the number of turns of acoil wound in the stator core. However, if the number of turns of thecoil is increased, the size of the stator core or the motor isinevitably increased which results in reduction in miniaturization.Accordingly, in order to improve the output of the motor withoutincreasing the size of the motor, a method of increasing a space factorof a coil wound around the stator core (e.g., by minimizing a dead spacebetween the stator core and a winding coil) may be considered.

In this regard, in place of using a ring-shaped coil (i.e., “ring-shapedwire”) having a circular section as a coil winding, a method of using aflat coil (i.e., “flat wire”) having a square section has been activelystudied. The flat coil may reduce the dead space and improve the spacefactor due to a shape of a section as compared with the ring-shapedcoil. However, the flat coil has a difficulty in a coil winding work ascompared to the ring-shaped coil. This is because the flat coil ismanufactured to have a wide cross-section as compared with the ringshaped coil in order to maximize the space factor so it is difficult touse a winding machine.

Accordingly, methods have been proposed for easily performing coilwinding work of the flat coil in a segment stator of the distributionwinding drive motor, in which a plurality of separated hairpins (i.e.,U-shape or V-shape) are inserted and engaged into each slot of thestator core, and in which sequentially welds between hairpins disposedin the slot are formed to continuously form a coil winding of the statorcore. A motor including a coil winding formed in this way isconventionally referred to as a “hairpin drive motor.” The coil windingstructure of the hairpin drive motor overcomes a device limit due to awinding machine and coil winding work is easily possible in a case ofthe flat coil, and may implement a miniaturized motor with high power byincreasing the space factor of the coil.

Since the hairpin drive motor described above is configured with acontinuous winding by inserting a leg of the hairpin in a slot of thestator core and welding an adjacent leg in a radial direction in theslot, a section adjacent to a hairpin on a different phase is generated.Insulation is weak in the above section so that there is a need for aseparate insulation structure. Meanwile, in a conventional statorwinding structure of a hairpin drive motor, if a rotating direction ofthe motor and a draw out position of one phase (e.g., a U-phase) aredetermined, a position of a different phase (e.g., V-phase or W-phase)may be determined in each slot with a predetermined pattern. In thiscase, a 3-phase draw out part and a neutral point draw out part may beformed as a pattern of a rule minimizing a pitch between phases in orderto simplify a winding structure of a hairpin by reducing a draw outlength of the winding coil.

However, since a conventional 3-phase draw output part has a coilwinding structure minimizing a patch between phases, a section adjacentto a hairpin of different phases is generated in an insertion directionof the hairpin inserted into a slot of the stator. Therefore, a sectionhaving a maximum potential difference is located in the adjacent sectionbetween phases, thereby causing an insulation problem of the motor.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the disclosure, andtherefore, it may contain information that does not form the related artthat is already known in this country to a person of ordinary skill inthe art.

SUMMARY OF THE DISCLOSURE

The present disclosure has been made in an effort to provide a statorwinding pattern of a hairpin driver motor having advantages ofminimizing a maximum potential difference at an adjacent section betweenphases by limiting a winding position of draw out parts having differentphases based on a draw out part of one phase.

Embodiments of the present disclosure provide: a stator winding patternof a hairpin drive motor including a stator with 8 poles and 48 slots ofa distribution winding where a hairpintype of flat coil is inserted intoa slot of a stator core and configured by a full pitch windingimplementing 6 pitches of 3 phases and 2 in parallel, the pitch being adistance between adjacent slots, characterized in that: first to fourthlayers are formed in the slot of the stator core in a radial directionof the stator core; and when a first layer or a fourth layer is set as adraw out part of one phase in an optional reference slot, a first drawout part of a different phase is formed in a draw out slot having 28pitches in a slot forward direction in a same layer based on thereference slot, and a second draw out part of the different phase isformed in a draw out slot having 20 pitches in a slot reverse directionin the same layer based on the reference slot.

In the stator winding pattern, neutral point draw out parts of threephases may be formed in the first layer by the draw out part of the onephase, a first neutral point draw out part of the different phase may beformed in the draw out slot having 28 pitches in the slot forwarddirection based on a neutral point draw out part of the one phase, and asecond neutral point draw out part of the different phase may be formedin the draw out slot having 20 pitches in the slot reverse directionbased on the neutral point draw out part of one phase.

In the stator winding pattern, the neutral point draw out parts of thethree phases are formed in the fourth layer by the draw out part of theone phase, the first neutral point draw out part of the different phaseis formed in the draw out slot having 28 pitches in the slot forwarddirection based on the neutral point draw out part of the one phase, andthe second neutral point draw out part of the different phase is formedin the draw out slot having 20 pitches in the slot reverse directionbased on the neutral point draw out part of the one phase.

In the stator winding pattern, the neutral point draw out parts of thethree phases are formed in the fourth layer by the draw out part of theone phase,the first neutral point draw out part of the different phaseis formed in the draw out slot having 28 pitches in the slot forwarddirection based on the neutral point draw out part of the one phase, andthe second neutral point draw out part of the different phase is formedin the draw out slot having 20 pitches in the slot reverse directionbased on the neutral point draw out part of the one phase.

Furthermore, embodiments of the present disclosure provide a statorwinding pattern of a hairpin drive motor including a stator with 8 polesand 48 slots of a distribution winding where a hairpin-type of flat coilis inserted into a slot of a stator core and configured by a full pitchwinding implementing 6 pitches of 3 phases and 2 in parallel (U1, U2/V1,V2/W1, W2), the 48 slots being referred to as first to 48th slot in aforward direction, characterized in that: first to fourth layers areformed in the slot of the stator core in a radial direction of thestator core; and when a fourth layer of a 16th slot is set as a U1 drawout part, a V1 draw out part is formed in a fourth layer of a 44th slot,a W1 draw out part is formed in a fourth layer of a 24th slot, a U2 drawout part is formed in a first layer of a 14th slot, a V2 draw out partis formed in the first layer of a 42nd slot, and a W2 draw out part isformed in a first layer of a 22nd slot.

In the stator winding pattern, U1, V1, and W1 neutral point draw outparts of three phases may be formed in the first layer by the U1 drawout part, and the U1 neutral point draw out part may be formed in afirst layer of an 8th slot, the V1 neutral point draw out part may beformed in a first layer of a 36th slot, and the W1 neutral point drawout part may be formed in a first layer of a 16th slot.

In the stator winding pattern, U2, V2, and W2 neutral point draw outparts of the three phases may be formed in the fourth layer by the U1draw out part, and the U2 neutral point draw out part may be formed inthe fourth layer of a 22nd slot, the V2 neutral point draw out part maybe formed in a fourth layer of a second slot, and the W2 neutral pointdraw out part may be formed in a fourth layer of a 30th slot.

In view of the above, embodiments of the present disclosure may minimizea maximum potential difference at an adjacent section between phases bylimiting a winding position of draw out parts having different phasesbased on a draw out part of one phase. Since a a maximum potentialdifference at an adjacent section between phases can be minimized,insulation performance of a drive motor may be ensured without using aseparate insulation component between stator coils having differentphases. Further, since a maximum potential difference at an adjacentsection between phases can be minimized, a coating thickness of a statorcoil can be reduced based on the same capacity of the motor.Accordingly, a copper use amount of the stator coil can be reduced, acost can be reduced, and motor efficiency can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed description, only certain embodiments of thepresent disclosure have been shown and described, simply by way ofillustration.

FIG. 1 is a diagram illustrating a stator winding pattern of a hairpindrive motor in accordance with embodiments of the present disclosure;

FIG. 2 is a diagram illustrating a potential difference between phasesof a stator winding pattern of a hairpin drive motor in accordance withembodiments of the present disclosure shown in FIG. 1;

FIG. 3 is a diagram illustrating a stator winding pattern of a hairpindrive motor according to a comparative example for describing anoperational effect of a stator winding pattern of a hairpin drive motorin accordance with embodiments of the present disclosure; and

FIG. 4 is a diagram illustrating a potential difference between phasesof a stator winding pattern of a hairpin drive motor in accordance witha comparative example shown in FIG. 3.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure will be described more fully hereinafter withreference to the accompanying drawings, in which embodiments of thedisclosure are shown. As those skilled in the art would realize, thedescribed embodiments may be modified in various different ways, allwithout departing from the spirit or scope of the present disclosure.Parts that are irrelevant to the description are omitted to clearlyillustrate the present disclosure, and like reference numbers designatelike constituent elements through the specification. Further, the sizeand thickness of each configuration shown in the drawings are optionallyillustrated for better understanding and ease of description, thepresent disclosure is not limited to shown drawings, and the thicknessis exaggerated for clarity of a plurality of parts and regions.

In the following detailed description, the terms “first” and “second”will be used to discriminate one component from the other component, butthe components may not be limited to the above terms. In addition, inthe following specification, unless explicitly described to thecontrary, the word “comprise” and variations such as “comprises” or“comprising” will be understood to imply the inclusion of statedelements but not the exclusion of any other elements. In the followingdescription, the suffixes “˜unit”, “˜means”, “˜part”, and “˜member” meanunits of a general configuration that perform at least one function oroperation.

It is understood that the term “vehicle” or “vehicular” or other similarterm as used herein is inclusive of motor vehicles in general such aspassenger automobiles including sports utility vehicles (SUV), buses,trucks, various commercial vehicles, watercraft including a variety ofboats and ships, aircraft, and the like, and includes hybrid vehicles,electric vehicles, plug-in hybrid electric vehicles, hydrogen-poweredvehicles and other alternative fuel vehicles (e.g., fuels derived fromresources other than petroleum). As referred to herein, a hybrid vehicleis a vehicle that has two or more sources of power, for example bothgasoline-powered and electric-powered vehicles.

Referring now to the disclosed embodiments, FIG. 1 is a diagramillustrating a stator winding pattern of a hairpin drive motor inaccordance with embodiments of the present disclosure.

As shown in FIG. 1, a stator winding pattern of a hairpin drive motor ofthe present disclosure is applicable to a drive motor for a hybridvehicle and/or electric vehicle to obtain a driving torque fromelectrical energy by an environmentally friendly vehicle (e.g., anelectric or hybrid vehicle). For example, the stator winding pattern ofthe hairpin drive motor in accordance with the present disclosure isapplicable to a permanent magnet synchronous motor (PMSM) as the abovedrive motor.

The PMSM includes a stator to generate a magnetic flux, a rotor spacedapart from the stator by a predetermined gap, and a permanent magnetinstalled at the rotor. The stator includes a stator core in which aplurality of steel plates are laminated. A plurality of slots are formedtoward a center shaft in the stator core in a radial direction. A statorcoil is wound around the slot. The stator coil is a hairpin type of flatcoil. For example, the stator coil has a pair of legs and has a U shapeor a V shape. The stator coil may include a flat coil having a squaresection.

The hairpin-type of stator coil is inserted into slots of a stator core,and end portions of a pair of legs protrude outside of the slot. Theprotruded portions of the legs are bent, welded, and electricallyconnected to each other. That is, a plurality of separated stator coilsare inserted and engaged in the slots of the stator core and the statorcoils are sequentially welded, and the embodiment is applicable to ahairpin drive motor formed therein with a coil winding of the stator.

Although the hairpin drive motor can be applied to a permanent magnettype of hairpin drive motor as a drive motor used in the environmentallyfriendly vehicle, the scope of the present disclosure is not limitedthereto. A technical scope of the present disclosure is applicable tovarious types and purposes of a hairpin drive motor.

Before describing the stator winding pattern of a hairpin drive motor inaccordance with an exemplary embodiment of the present disclosure, thestator core includes a number of slots being a multiple of the number ofpoles x the number of phases. For example, embodiments of the presentdisclosure are applicable to a full pitch winding stator windingstructure including a stator with 8 poles and 48 slots of a distributionwinding where a hairpin type of flat coil is wound around slots of thestator core, and implementing 3 phases with 2 in parallel (U1, U2/V1,V2/W1, W2).

The 48 slots (i.e., slot numbers 1 to 48) are radially formed from ahollow portion of the stator. The 48 slots 1 to 48 may have the sameshape. Further, the 48 slots 1 to 48 may have a multi-layered structure.Each slot may include four layers of first to fourth layers in the orderfrom an outer peripheral side to an inner peripheral side of the statorcore in a radial direction of the stator core.

Further, the 3 phases with 2 in parallel (U1, U2/V1, V2/W1, W2) meansphases having different positions of an N-pole and an S-pole of anelectro-magnetized stator core by allowing a current to flow throughdifferent paths in the stator coil.

Hereinafter, a progress direction from a first slot to a 48th slot inthe stator core refers to a slot forward direction (i.e., motor rotationdirection), and a progress direction from a 48th slot to a first slot inthe stator core refers to a slot reverse direction (i.e., motor rotationopposite direction). Further, (+) and (−) in the 3 phases with 2 inparallel (U1, U2/V1, V2/W1, W2) means a flowing direction of the currentin each phase.

Moreover, embodiments of the present disclosure include a stator with 8poles and 48 slots. When one row between adjacent slots is determined as1 pitch, the present disclosure is applicable to a stator windingstructure of a full pitch winding 6 pitches implementing the 3 phaseswith 2 in parallel (U1, U2/V1 , V2/W1, W2). For example, in a statorwinding structure of a full pitch winding 6 pitches implementing the 3phases with 2 in parallel, if a U1+ phase is set to two optionaladjacent slots (fourth layer of 15th and 16th slots in the drawing), aU1+ phase is disposed in 27th and 28th slots which are slots of 12pitches in the same layer. When a condition of a full pitch winding 6pitches is considered based on the 15th and 16th slots, a U2− phase maybe disposed in a fourth layer of 21st and 22nd slots corresponding to aslot of 6 pitches. In addition, U1− phases may be disposed in a thirdlayer of the slots based on 21st and 22nd slots, respectively.

Further, U2+ phases are disposed in a third layer of the slots based onthe 15th and 16th slots, respectively. U1+ phases are disposed in thesecond layer of 14th and 15th slots corresponding to the 15th and 16thslots, respectively, while U2+ phases are disposed in the first layer ofthe 14th and 15th slots, respectively. Moreover, U2− phases are disposedin the second layer of the 20th and 21st slots corresponding to the 21stand 22nd slots, respectively, while U1− phases are disposed in the firstlayer of the 20th and 21st slots, respectively. Different phases aremoved in one direction (slot forward direction or slot reversedirection) by a 1 pitch slot by disposing the different phases in thefirst and second layers of 14th and 15th, and 20th and 21st slots basedon the third and fourth layers of 15th and 16th, and 21st and 22nd slotsfor the purpose of improving NVH performance of the motor by applying askew to a stator coil.

Furthermore, in an example as described above, W1 and W2 phases and V1and V2 phases are sequentially disposed in a slot forward directionbased on U1 and U2 phases and are disposed in the same manner as in U1and U2 phases, each phase of 3 phases with 2 in parallel (U1, U2/V1,V2/W1, W2) as shown may be regularly disposed in a full layer of 48slots as the full pitch winding 6 pitches. Since a method of forming awinding pattern as described above in the stator winding structure ofthe full pitch winding 6 pitches implementing 3 phases with 2 inparallel is well known in the art, a detailed description thereof isomitted from the specification.

The embodiments of the present disclosure as described above feature astructure capable of minimizing a maximum potential difference at anadjacent section between phases by limiting a winding structure of drawout parts having different shapes based on a draw out part of one phasebased on a stator winding pattern for a hairpin drive motor.Accordingly, in the stator pattern of a hairpin drive motor inaccordance with the present disclosure, if an optional reference slot isset to a draw out part U1 or U2, a draw out part of a different shape V1or V2 and a draw out part of a different shape W1 or W2 based on thereference slot may be formed in a draw out slot having 28 pitches in aslot forward direction or a draw out slot having 20 pitches in a slotreverse direction in the same layer (first layer or fourth layer). Thatis, the draw out part of a different shape V1 or V2 may be formed in adraw out slot of 28 pitches in a slot forward direction or of 20 pitchesin a slot reverse direction based on a draw out part U1 or U2 of oneshape in the same layer (first layer or fourth layer). Further, a drawout part of the different phase W1 or W2 may be formed in a draw outslot having 28 pitches in a slot forward direction or 20 pitches in aslot reverse direction based on a draw out part of a different phase V1or V2 in the same layer (first layer or fourth layer).

In addition, draw out parts of 3 phases may be formed in the same layer(first layer or fourth layer) of the draw out part by a preset draw outpart U1 or U2 of one shape. Based on a neutral point draw out part NU1of one phase, a neutral point draw out part of a different shape NV1 anda draw out part of a different phase NW1 in the first layer may beformed in a draw out slot having 28 pitches in a slot forward directionor 20 pitches in a slot reverse direction, respectively. That is, theneutral point draw out of a different shape NV1 may be formed in a drawout slot having 28 pitches in a slot forward direction or 20 pitches ina slot reverse direction based on a neutral point draw out part NU1 inthe first layer.

Further, a neutral draw out part of the different phase NW1 may beformed in a draw out slot having 28 pitches in a slot forward directionor 20 pitches in a slot reverse direction based on a draw out part of adifferent phase NV1 in the first layer. Moreover, based on a neutralpoint draw out part NU2 of one phase, a neutral point draw out of adifferent shape NV2 and a neutral point draw out part of a differentshape NW2 may be formed in a draw out slot having 28 pitches in a slotforward direction or 20 pitches in a slot reverse direction in thefourth layer. That is, the neutral point draw out part of a differentshape NV2 may be formed in a draw out slot having 28 pitches in a slotforward direction or 20 pitches in a slot reverse direction based on theneutral point draw out part NU2 of one shape in the fourth layer.Further, the neutral point draw out part of a different shape NW2 may beformed in a draw out slot having 28 pitches in a slot forward directionor 20 pitches in a slot reverse direction based on a neutral point drawout part of a different shape NV2 in the fourth layer.

Hereinafter, the stator winding pattern of the hairpin drive motor inaccordance with embodiments of the present disclosure will be describedin detail with reference to FIG. 1.

First to fourth layers L1, L2, L3, and L4 may be formed in 48 slots 1-48in a radial direction of a stator core based on when respective slots 1to 48 are disposed in the order from a first slot to a 48th slot in theforward direction.

First, for example, if a fourth layer L4 of a 16th slot is set to a U1draw out part 11 as a preset reference slot, a V1 draw out part 21 maybe formed in a fourth layer L4 of a 44th slot distant from a 16th slotof the U1 draw out part 11 in a slot forward direction by 28 pitches orin the slot reverse direction by 20 pitches.

In addition, a W1 draw out part 31 may be formed in a fourth layer L4 ofa 24th slot distant from a 44th slot of the V1 draw out part 21 in aslot forward direction by 28 pitches or in the slot reverse direction by20 pitches based on a 44th slot of the V1 draw out part 21. That is, aW1 draw out part 31 may be formed in a fourth layer L4 of a 24th slotdistant from a 16th slot of the U1 draw out part 11 in a slot forwarddirection by 8 pitches based on a 16th slot of the U1 draw out part

Meanwhile, the U2 draw out part 12 is formed in the first layer L1 ofthe 14th slot based on a 4th layer L4 of a 16th slot of the U1 draw outpart 11. The V2 draw out part 22 may be formed in a first layer L1 of a43rd slot distant from a 14th slot of the U2 draw out part 12 in a slotforward direction by 28 pitches or in the slot reverse direction by 20pitches based on the 14th slot of the U2 draw out part 12.

Further, the W2 draw out part 32 may be formed in a first layer L1 of a22nd slot distant from a 42nd slot of the V2 draw out part 22 in a slotforward direction by 28 pitches or in the slot reverse direction by 20pitches based on the 42nd slot of the V2 draw out part 22. That is, theW2 draw out part 32 may be formed in a first layer L1 of a 22nd slotdistant from a 14th slot of the U2 draw out part 12 in a slot forwarddirection by 8 pitches based on the 14th slot of the U2 draw out part12.

In addition, neutral point draw out parts N11, N21, and N31 of 3 phasesU1, V1, and W1 may be formed in a first layer L1 of slots by a U1 drawout part 11 of the 16th slot set as an optional reference point. The U1neutral point draw out part N11 is formed in a first layer L1 of aneighth slot based on a fourth layer L4 of a 16th slot of the U1 draw outpart 11. The V1 neutral point draw out part N21 may be formed in a firstlayer L1 of a 36th slot distant from a 8th slot of the U1 neutral drawout part N11 in a slot forward direction by 28 pitches or in the slotreverse direction by 20 pitches based on the 8th slot of the U1 neutraldraw out part N11.

Further, the W1 neutral point draw out part N31 may be formed in a firstlayer L1 of a 16th slot distant from a 36th slot of the V1 neutral drawout part N21 in a slot forward direction by 28 pitches or in the slotreverse direction by 20 pitches based on the 8th slot of the U1 neutraldraw out part N11. That is, the W1 neutral point draw out part N31 maybe formed in a first layer L1 of a 16th slot distant from an 8th slot ofthe U1 neutral draw out part N11 in a slot forward direction by 8pitches based on the 8th slot of the U1 neutral draw out part N11.

Meanwhile, neutral point draw out parts N12, N22, and N32 of 3 phasesU2, V2, and W2 may be formed in a fourth layer L4 of slots by a U1 drawout part 11 of the 16th slot set as an optional reference point. The U2neutral point draw out part N12 is formed in a fourth layer L4 of a 22ndslot based on a fourth layer L4 of a 16th slot of the U1 draw out part11. The V2 neutral point draw out part N22 may be formed in a fourthlayer L4 of a second slot distant from a 22nd slot of the U2 neutraldraw out part N12 in a slot forward direction by 28 pitches or in theslot reverse direction by 20 pitches based on the 8th slot of the U2neutral draw out part N12.

Further, the W2 neutral point draw out part N32 may be formed in afourth layer L4 of a 30th slot distant from a second slot of the V2neutral draw out part N22 in a slot forward direction by 28 pitches orin the slot reverse direction by 20 pitches based on the 8th slot of theU1 neutral draw out part N11. That is, the W2 neutral point draw outpart N32 may be formed in a fourth layer L4 of a 30th slot distant froma 22nd slot of the U2 neutral draw out part N12 in a slot forwarddirection by 8 pitches based on the 22nd slot of the U2 neutral draw outpart N12. Therefore, according to the stator winding pattern of ahairpin drive motor in accordance with embodiments of the presentdisclosure, the draw out part V1 or V2 of a different phase and the drawout part W1 or W2 of a different phase may be configured in a draw outslot distant from the preset draw out part U1 or U2 of one phase whichis optionally set in a slot forward direction by 28 pitches or in theslot reverse direction by 20 pitches, respectively.

Meanwhile, as shown in FIG. 2, for example, when a current flows to apath of a U1 phase, since a stator coil of 16 turns (i.e., 16 hairpinstator coil) having a pair of legs is configured, a reference voltage of32 volts becomes gradually reduced proportional to a predeterminedmultiple in the direction of the U1 neutral point draw out part N11 fromthe U1 draw out part 11. For example, when a voltage at the U1 draw outpart 11 is 32 V, a voltage at the U1 neutral point draw out N11 becomes0 V. That is, a reverse breakdown voltage is generated per leg of astator coil of 16 turns in the direction of the U1 draw out part 11 fromthe U1 neutral point draw out part N11 so that a voltage is increased to0 V to 32 V.

Accordingly, the V1 draw out part 21 and the W1 draw out part 31 beingdifferent draw out parts based on the U1 draw out part 11, areconfigured in draw out slots of 28 pitches in the slot forward directionor of 20 pitches in the slot reverse direction in the same layer.Furthermore, since a voltage is reduced proportional to a predeterminedmultiple in the direction of the draw out parts N11, N21, and N31 ofeach phase U1, V1, and W1 from the draw out parts 11, 21, and 31 of eachphase U1, V1, and W1 by shifting the draw out parts 21 and 31 ofdifferent phases V1 and W1 based on the U1 draw out part 11 bypredetermined sections (i.e., 28 pitches in the slot forward directionor 20 pitches in the slot reverse direction), a maximum potentialdifference at an adjacent section between phases may be minimized. Thatis, since the draw out parts 21 and 31 of different phases V1 and W1 areconfigured in a position between the U1 draw out part 11 and the U1neutral point draw out part N11 where a voltage is reduced by apredetermined section (28 pitches in the slot forward direction or 20pitches in the slot reverse direction), the maximum potential differenceat an adjacent section between phases may be significantly reduced.

Hereinafter, an operational effect of the stator winding pattern of thehairpin drive motor according to embodiments of the present disclosureas described above is described by comparing with comparative examplesof FIG. 3 and FIG. 4.

As shown in FIG. 3, if an optional reference slot is set to a draw outpart U1 or U2 of one phase in the comparative example corresponding toembodiments of the present disclosure, a draw out part of a differentphase V1 or V2 and a draw out part of a different phase W1 or W2 areconfigured in a draw out slot distant from the reference slot in theslot forward direction by 4 pitches, respectively.

In detail, for example, if a fourth layer L4 of a 16th slot is set tothe U1 draw out part 11, the V1 draw out part 21 may be formed in afourth layer L4 of a 20th slot distant from the 16th slot of the U1 drawout part 11 in the slot forward direction. Further, the W1 draw out part31 may be formed in the fourth layer L4 of the 24th slot distant fromthe 16th slot of the U1 draw out part 11 in the slot forward directionby 8 pitches based on the 16th slot of the U1 draw out part 11. That is,the W1 draw out part 31 may be formed in the fourth layer L4 of the 24thslot distant from the 20th slot of the V1 draw out part 21 in the slotforward direction by 4 pitches.

Meanwhile, in the comparative example, the U2 draw out part 12 is formedin a first layer L1 of the 14th slot based on a fourth layer L4 of the16th slot of the U1 draw out part 11. The V2 draw out part 22 may beformed in the first layer of the 18th slot distant from the 14th slot ofthe U2 draw out part 12 in the slot forward direction by 4 pitches basedon the 14th slot of the U2 draw out part 12. Based on the 14th slot ofthe U2 draw out part 12, the W2 draw out part 32 may be formed in thefirst layer L1 of the 22th slot distant from the 14th slot of the U2draw out part 12 in the slot forward direction by 8 pitches. That is,the W2 draw out part 32 may be formed in a first layer L1 of the 22ndslot distant from the 18th slot of the V2 draw out part 22 in the slotforward direction by 4 pitches.

Further, in the comparative example, a U1 neutral point draw out partN11 is formed in the first layer L1 of the 8th slot based on a fourthlayer L4 of a 16th slot of the U1 draw out part 11. A V1 neutral pointdraw out part N21 may be formed in the first layer L1 of the 12th slotdistant from the 8th slot of the U1 neutral point draw out part N11 inthe slot forward direction by 4 pitches. In addition, the W1 neutralpoint draw out part N31 may be formed in the first layer L1 of the 16thslot distant from the 8th slot of the U1 neutral point draw out part N11in the slot forward direction by 8 pitches. That is, the W1 neutralpoint draw out part N31 may be formed in the first layer L1 of the 16thslot distant from a 12th slot of the V1 neutral point draw out part N21in the slot forward direction by 4 pitches. In the same manner, a U2neutral point draw out part N12 is formed in a fourth layer L4 of the22nd slot based on the fourth layer L4 of a 16th slot of the U1 draw outpart 11 in the comparative example.

In addition, a V2 neutral point draw out part N22 may be formed in thefourth layer L4 of the 26th slot distant from the 22nd slot of the U2neutral point draw out part N12 in the slot forward direction by 4pitches. Moreover, a W2 neutral point draw out part N32 may be formed inthe fourth layer L4 of the 30th slot distant from the 22nd slot of theU2 neutral point draw out part N12 in the slot forward direction by 8pitches. That is, the W2 neutral point draw out part N32 may be formedin the fourth layer L4 of the 30th slot distant from the 26th slot ofthe V2 neutral point draw out part N22 in the slot forward direction by4 pitches. Therefore, the draw out part V1 or V2 of a different phaseand the draw out part W1 or W2 of a different phase may be configured ina draw out slot distant from the preset draw out part U1 or U2 of onephase in a slot forward direction by 4 pitches, respectively.

In the meantime, in the comparative example, as shown in FIG. 4, when acurrent flows to a path of a U1 phase, a V1 draw out part 21 isconfigured in the draw out slot distant from the U1 draw out part 11 inthe slot forward direction by 4 pitches, and a W1 draw out part 31 isconfigured in the draw out slot distant from the V1 draw out part 21 inthe slot forward direction by 4 pitches. Accordingly, since draw outparts 21 and 31 of different phases V1 and W1 are configured closest tothe U1 draw out part 11 based on the U1 draw out part 11, a voltagebecomes reduced proportional to a predetermined multiple in thedirection of neutral point draw out parts N11, N21, and N31 of eachphase from draw out parts 11, 21, and 31 of each phase. When taking intoconsideration the above characteristic, a maximum potential differenceoccurs at an adjacent section of draw out parts 11, 21, and 31 of eachphase having a relatively high voltage due to reduction of the pitchbetween the draw out parts 11, 21, and 31 of each phase.

For example, a maximum potential difference between a U1 phase and a V1phase in the comparative example is described. Under the condition ofreducing a reference voltage of 32 V in the direction of the U1 neutralpoint draw out part N11 from the U1 draw out part 11 proportional to apredetermined multiple, since E U1=31 sine and E V1=32 sin(θ−120°), themaximum potential difference between a U1 phase and a V1 phaserepresents 54.56 V. In this way, a section having the maximum potentialdifference is included in an adjacent section of the draw out parts 11,21, and 31 having a relatively high voltage due to reduction of thepitch between draw out parts 11, 21, and 31 of each phase in thecomparative example so that an insulation problem of the motor may becaused.

As in the comparative example, the pitch between draw out parts 11, 21,and 31 and neutral point draw out parts N11, N21, and N31 of 3 phases isminimized for the purpose of collecting the draw out parts 11, 21, and31 and the neutral point draw out parts N11, N21, and N31 of 3 phasesclose to each other and of reducing draw out length of the draw outparts 11, 21, and 31 and the neutral point draw out parts N11, N21, andN31 of 3 phases. However, in the stator winding pattern of a hairpindrive motor in accordance with embodiments the present disclosure, asdescribed above with reference to FIG. 1 and FIG. 2, since draw outparts 21 and 31 of different phases V1 and W1 are configured at aposition where a voltage is reduced from the U1 draw out part 11 to theU1 neutral point draw out part N11 by a predetermined section (28pitches in the slot forward direction or 20 pitches in the slot reversedirection), the potential difference of the adjacent section betweenphases may be minimized. For example, a maximum potential differencebetween a U1 phase and a V1 phase in accordance with embodiments of thepresent disclosure is described. Under the condition of reducing areference voltage of 32 V in the direction of the U1 neutral point drawout part N11 from the U1 draw out part 11 proportional to apredetermined multiple, since E U1=31 sine and E V1=32 sin(θ−120°), themaximum potential difference between a U1 phase and a V1 phaserepresents 50.27 V.

According to the stator winding pattern of the hairpin drive motor inaccordance with the present disclosure as described above, the maximumpotential difference at an adjacent section between phases may beminimized by shifting draw out parts of different phases by apredetermined section (28 pitches in the slot forward direction or 20pitches in the slot reverse direction) from the draw out part of onephase. That is, in accordance with an exemplary embodiment of thepresent disclosure, the maximum potential difference at an adjacentsection between phases may be reduced by about 7.89% as compared withthe above comparative example. Accordingly a maximum potentialdifference at an adjacent section between phases may be minimized bylimiting a winding position of a draw out part having different phasesbased on a draw out part of one phase

Therefore, since embodiments of the present disclosure may minimize themaximum potential difference at an adjacent section between phases,insulation performance of the drive motor may be ensured without using aseparate insulation component between stator coils of different phases.Further, since the maximum potential difference at an adjacent sectionbetween phases may be minimized, a coating thickness of the stator coilmay be reduced based on capacity of the same motor so that a use amountof copper of the stator coil may be reduced, a cost may be reduced, andmotor efficiency may be improved.

Embodiments of the present disclosure are disclosed herein, but thepresent disclosure is not limited to the disclosed embodiments. On thecontrary, the present disclosure is intended to cover variousmodifications and equivalent arrangements included within the appendedclaims and the detailed description and the accompanying drawing of thepresent disclosure.

<Description of symbols> 11 U1 draw out part 12 U2 draw out part 21 V1draw out part 22 V2 draw out part 31 W1 draw out part 32 W2 draw outpart L1-L4 first to fourth layers N11 U1 neutral point draw out part N12U2 neutral point draw out part N21 V1 neutral point draw out part N22 V2neutral point draw out part N31 W1 neutral point draw out part N32 W2neutral point draw out part

What is claimed is:
 1. A stator winding pattern of a hairpin drive motorincluding a stator with 8 poles and 48 slots of a distribution windingwhere a hairpintype of flat coil is inserted into a slot of a statorcore and configured by a full pitch winding implementing 6 pitches of 3phases and 2 in parallel, the pitch being a distance between adjacentslots, characterized in that: first to fourth layers are formed in theslot of the stator core in a radial direction of the stator core; andwhen a first layer or a fourth layer is set as a draw out part of onephase in an optional reference slot, a first draw out part of adifferent phase is formed in a draw out slot having 28 pitches in a slotforward direction in a same layer based on the reference slot, and asecond draw out part of the different phase is formed in a draw out slothaving 20 pitches in a slot reverse direction in the same layer based onthe reference slot.
 2. The stator winding pattern of a hairpin drivemotor of claim 1, wherein neutral point draw out parts of three phasesare formed in the first layer by the draw out part of the one phase, afirst neutral point draw out part of the different phase is formed inthe draw out slot having 28 pitches in the slot forward direction basedon a neutral point draw out part of the one phase, and a second neutralpoint draw out part of the different phase is formed in the draw outslot having 20 pitches in the slot reverse direction based on theneutral point draw out part of one phase.
 3. The stator winding patternof a hairpin drive motor of claim 2, wherein the neutral point draw outparts of the three phases are formed in the fourth layer by the draw outpart of the one phase, the first neutral point draw out part of thedifferent phase is formed in the draw out slot having 28 pitches in theslot forward direction based on the neutral point draw out part of theone phase, and the second neutral point draw out part of the differentphase is formed in the draw out slot having 20 pitches in the slotreverse direction based on the neutral point draw out part of the onephase.
 4. A stator winding pattern of a hairpin drive motor including astator with 8 poles and 48 slots of a distribution winding where ahairpin-type of flat coil is inserted into a slot of a stator core andconfigured by a full pitch winding implementing 6 pitches of 3 phasesand 2 in parallel (U1, U2/V1, V2/W1, W2), the 48 slots being referred toas first to 48th slot in a forward direction, characterized in that:first to fourth layers are formed in the slot of the stator core in aradial direction of the stator core; and, when a fourth layer of a 16thslot is set as a U1 draw out part, a V1 draw out part is formed in afourth layer of a 44th slot, a W1 draw out part is formed in a fourthlayer of a 24th slot, a U2 draw out part is formed in a first layer of a14th slot, a V2 draw out part is formed in the first layer of a 42ndslot, and a W2 draw out part is formed in a first layer of a 22nd slot.5. The stator winding pattern of a hairpin drive motor of claim 4,wherein U1, V1, and W1 neutral point draw out parts of three phases areformed in the first layer by the U1 draw out part, and the U1 neutralpoint draw out part is formed in a first layer of an 8th slot, the V1neutral point draw out part is formed in a first layer of a 36th slot,and the W1 neutral point draw out part is formed in a first layer of a16th slot.
 6. The stator winding pattern of a hairpin drive motor ofclaim 5, wherein U2, V2, and W2 neutral point draw out parts of thethree phases are formed in the fourth layer by the U1 draw out part, andthe U2 neutral point draw out part is formed in the fourth layer of a22nd slot, the V2 neutral point draw out part is formed in a fourthlayer of a second slot, and the W2 neutral point draw out part is formedin a fourth layer of a 30th slot.